Metal petroleum sulfonates



WEIGHT PER CENT ASH April 28, 1959 w. N.- AXE EIAL METAL PETROLEUM SULFONATES Filed Dec. 17, 1956 -'AC|D ADDTON IN 30 SECONDS, ADDlTIONAL STIRRING,

30 SECONDS. O-ACID ADDlTlON l0 MINUTES OR MORE WTH STIRRING FOR REMAINDER 0F REACTION TIME. 2 l

TIME \N HOURS INVENTORS W. N. AXE

J. 7i GRAGSON "Hm 9 M A T TORNEYS drous ammonia, extraction of sludge. with sodium hydroxide resulted in a very stable emul- .and;, detergency.

, sired metal.

United States Patent 2,884,445 METAL PETROLEUM SULFONATES ,William N. Axe and James T. Gragson, Bartlesville, 0kla.,

assignors to Phillips Petroleum Company, a corporation of Delaware This invention relates to a method for making an improved metal petroleum sulfonate and to a lubricant embodying such metal petroleum sulfonate as an additive.

Copending application, Serial No. 478,839, filed December 30, 1954, by W. B. Whitney, describes a method for preparing oil soluble metal petroleum sulfonates from highly refined, solvent extracted, high molecular weight petroleum stocks by treatment with a sulfonating agent, neutralization of the resulting oil-acid mixture with anhyan ammonium petroleum sulfonate with an organic solvent, and conversion of the ammonium petroleum sulfonate to the metal petroleum sulfonate by reaction with an excess of a metal salt or hydroxide. It had heretofore been considered impossible to produce oil-soluble sulfonates from high molecular weight hydrocarbon inga viscosity of about 200 fractions such as a Bright Stock hav- SUS at 210 F. because treatment of such highly refined lubricating oil stocks with fuming sulfuric acid produced no precipitate of acid Neutralization of the resulting acid-oil mixture sion. Extraction of the petroleum sulfonate from such emulsion produced a low yield of product which was, in

each case, contaminated with inorganic salts.

" In accordance with the present invention, an improved process is provided for making metal petroleum sulfonates from heavy oil stocks. .con'tentof oil-soluble metal petroleum sulfonates pre- We have discovered that the ash pared from highly refined, solvent-extracted high molecular weight petroleum stocks is dependent upon the contact time ofi.the sulfonating agent with the oil and also the manner in which the contact is attained. By the proc- ;ess of our invention, an additive is obtained having a high metal and ash content with resulting high activity It is an object of this invention to provide a process for increasing the yield of metal petroleum sulfonates prepared from high molecular weight petroleum stocks. It is also an object of this invention to provide an improved metal petroleum sulfonate useful as a lubricating oil additive. It is a further object of this invention to provide a means for preparing a metal petroleum sulfonate having a high ash content. It is still an .other object of this invention to provide a simplified process for the preparation of metal petroleum sulfonates of high quality and in high yield. Other and further objects of this invention will be apparent to one upon study of the disclosure of the present invention.

Broadly, the invention contemplates admixing the oil to be-sulfonated with the sulfonation agent in a short period of time, preferably not exceeding minutes, vigorously agitating the mixture to attain intimate contact ofthe oil with the sulfonation agent and then allowing the mixture to rest in a quiescent state for a period of one to one and one-half hours and then neutralizing the reaction mixture with the oxide or hydroxide of the de- An excess of the base is used so as to assure complete neutralization. The neutralized reaction product, is then diluted with an inert organic solvent, heat- Patented Apr. 28, 1959 ice 2 1 ed to expel moisture present, after which the metal petroleum sulfonate together with unreacted oil is separated from the inorganic salts by centrifugation, filtration, decanting, or other known means of separation. The product can be used in the form in which it is obtained or can be concentrated by removal of a portion or all of the unreacted oil by a separation step such as propane fractionation. Thus, a high quality lubricant additive is obtained which can be mixed with lubricating oil of, say SAE-SW to SAE-SOgrade in an amount of 0.1 to 20 percent by weight based on the oil whereby a high detergency oil with improved characteristics is obtained. The additive of this invention is also useful in the formation of greases upon addition of suitable thickening agents.

The drawing is a graphical illustration of the advantages which are gained by practice of the invention.

According to more specific aspects of the invention, the starting material is a refined lubricating oil stock such as a de-asphalted and solvent-refined petroleum fraction having a viscosity range between about 120 and 700 SUS at 210 F. An especially preferred sulfonation stock is a propane-fractionated, solvent-extracted and de-waxed Mid-Continent oil of about 200 to 235 SUS at 210" F. having a viscosity index of about to or higher.

In the sulfonation step, the oil starting material is intimately contacted with a sulfonation agent of which fuming sulfuric acid and chlorosulfonic acid are especially suitable. A temperature within the range of 50 to 200' F., and preferably to F. is maintained during the sulfonation together with an acid-to-oil weight ratio of 0.l75:l to 1:1 using 20 percent oleum. An acid-oil weight ratio of about 0.311 to about 0.6:1 is preferred from a standpoint of yield, reaction rate and color of product. When a high ratio of acid to oil is employed the product is dark, almost black, and tarry in contrast to the red, resinous product obtained employing the preferred acid to oil ratio. It is believed that oxidation occurs at high acid to oil ratios. The sulfonation agent is preferably added to the oil as rapidly as possible and with vigorous agitation. The agitation is continued only so long as is required to assure satisfactory dispersion of the sulfonation agent in the oil. The mixture is then allowed to rest in a quiescent state for the required reaction time after which it is immediately neutralized with an excess of the desired metal oxide or hydroxide. The reaction temperature is maintained during the time the mixture is quiescent.

All metals are suitable for preparing the metal petroleum sulfonates of this invention. Metals which have been found to be particularly suitable for preparing the metal petroleum sulfonates include barium, calcium, lithium, potassium, nickel, cobalt, cadmium, silver, iron, aluminum, copper, magnesium, lead, beryllium, mercury, sodium, tin, and zinc. The alkaline earth metals are preferred and barium and calcium are especially preferred in preparing metal petroleum sulfonates for use as addiitves in lubricants.

The following examples will illustrate the invention but are not to be construed as limiting the invention.

EXAMPLE I A solvent refined and de-waxed lubricating oil fraction containing an average of about 52 carbon atoms per molecule derived from a Mid-Continent petroleum and having a viscosity of 208 SUS at 210 F. and a viscosity index of 96 was sulfonated with 20 percent fuming sulfuric acid at an acid-to-oil ratio of 0.4. The sulfonation was carried out in a reaction vessel equipped with a stirrer and 5 runs were made in the following manner: the fuming sulfuric acid was added to the oil at a starting temperature of about 65 F. Fuming sulfuric acid was added with rapid stirring in a period of 30 seconds "time shown in and after an additional 30 seconds stirring the stirrer was removed and the mixture allowed to remainmotionless at a temperature maintained at 130 F. for the re- -n1ainder-of the reaction time. The reaction rnixtu're'was tlien "neutralized with an excessof calcium hydroxide *slurrieli in "water. The neutralized material was then stripped-of water by heating to about 400 F. and was then diluted withaboht 3 volumes otfpentane and centrifug'ed to remove inorganic salts. The 'pentane was then-evaporated and a sample analyzed for 'ash. The

-data are E'pre'se'nted in Table -I and are .plotted in the Samples of'the oil described in Example I were sulif "ated with 20 percent fuming sulfuric acid with an "acid to-oil ratio of 0.4 in the following manner: the reaction vessel'equipped'with afstirrer was charged with the oil and the a Table II and stirring was maintained at 130 Efforthe total reaction time shown in Table II Tafter which the "material was neutralized and treated in thejsarhe manner as described in Example I. The results I fuming sulfuric acid was added in the ;0f runs-are presented in Table II and. are graphical- 'lydllustrated in the'drawi'ng.

Table '11 ni h Total Reaction Time of Acid Content,

Time Addition 1 Weight Percent 15 minutes"; in minutes'.. 4. 42 35 minutes 15 minutes.-. 4. 8 3 45 minute A l 4. 97 v 6. 37 e 5. 5 a I 5. 4s 4 hours, 25 *25 minutes; 4. 72 minutes. t I r 7 hours 5 hours 3. 66

flme'ot acid'nddltion inclh'ded in total rcactioii'thne. i

g, Stood72-hours at room temperature without'stirring-before nentra'llcation.

EXAMPLE HI The "data shown in Table :plant operation'under two sets of conditions. These con- III were obtained in pilot ditions were: (1') the acid and oil were mixed in a cone trifugalfpump and then passed into a jacketedsteel pipe andallowed to stand for the required residence time; (2). the acid andoil were "mixed in acent'rifugal pump-and the iprodiict was allowed -to stand inglass beakers at theretjuiredrtemperature for the desiredresidence time. a In all cases the samples after standing for the'desired residence time were neutralized with an excessof calcium hydroxide slurried in water. The water was'evaporated by heating to about 400 F., the residue was cooled, diluted with pentane and centrifuged to remove inorganic salts. The pentane solvent wasevaporated and the ash content determined on the residue.

Table 1'11 .DQND 'T 'NA 'Ac'id-bil Residence Ash, Temperature, F. Ratio Time, Weight g minutes Percent o. 44 g is 15.34 0.42 63- 5. 93

The data of the examples show the increase in the exmation is increased -by'rapid acid addition .followed' b'y a soaking period or one to *one and "a half hours. data in the examples also show that anacid oilcbritat time of les's th'a'none hour'or more than one and a'halt' hours decreases the -yieldo'f sulfonate asr'efiected'bywthe 'decre'as'e in ash content. One'expl'anation of this may that a contact time of less than' one'hour is not sufiicient forcornpletesulfonation while a contact time in excess of one and 'a 'h'alf hours permits decomposition of-those sulfonic acids unstable 'in the presence of concentrated sulfuric acid. I 7

Variations and modifications are possible within *the scope of the disclosure of the l'present invention the es- 'se'nceof which is the discovery-that the'extent of'sulfona- "tionof' a highly refined, high viscosity lube foil fraction can be in'creased by rapid. addition of the sulfonation agent followed by 'asoaking period of'aboutan'honr toanholir and a half. I That whichis claimedis: 1 V 1. The process' of 'niaking an alkaline earth'nietalpetfoleurn sillfonate "whichcomprises "addin'g'oleum to rajropane-fractionated, 'solvent extracted and de-waxed Inbricating oil stock (having a viscosity of "about 200 to 230 SUS at 210 F. in a period o'f about one minute and with agitation; maintaining the resulting mixture quiescent for aboutf'one and'one half'hours at reaction temperature; neutralizing the mixture with an alkaline earth metal hydroxide; diluting the mixtiire "with about three volumes of 'pentane; and recovering the "resulting "alkaline e'arthrneta'l petroleumsulfonate.

'2. The "process of claim 1 wherein the alkaline 'inetal-is-calcium. v

'3. The process of claim. l wherein the alkaline earth metal is barium. I i

4. The process of claim 1 wherein thealkalineehrth nietal-is'ina'gnesium. I

5.- The process offc'laim 1- wherein the alkaline earth I "6.;Th'e proces'sfor making-a'metal petroleum sulforiate which comprises addingoleumat an acid-to-oilwei'ght ratio of 0.2 to 0.7 to a 'de-aspha'l ted, solvent-refined lubricating oil stock having a viscosity of about 120 to 700 SUS at 210 F. within ape'riod of about lominutes "and with agitation; maintaining the resulting mixture quiescent for a time in the range of one to one and onehalf hours at aternperature in the range to 1 50' F2; neutralizing the reaction mixture with a basic 'inetal compound; and recovering the metal petroleum sulfon'ate.

7. In the preparation of metal etroleum sulfonates wherein a 'de-as'phalted, solvent-refined lubricating oil stock having 'a viscosity of about 120 to 700 SUS"at=210' F. is sulfonated 'withfa sulfon'ation agent at a temperature in the range of about 50 to 200 'sulfo'nation is neutralized and converted to the metal petroleum sulfo'nate, the improvement comprising conducting the sulfo'nation step jby 'adding the sulfonation agent to the oil within a periodof timeless than "10minntes and with agitation; maintaining'the reaction F., "and the prtiductiif quiescent for a period of time in the range of one to one and one-half hours at the reaction temperature before neutralizing the reaction product; and recovering the metal petroleum sulfonate.

8. The process of claim 7 wherein the reaction mixture is neutralized with a basic metal compound; the reaction mixture is diluted with from 1 to 5 volumes of an inert organic diluent; and the metal petroleum sulfonate is recovered by centrifugation.

9. The process of claim 7 is neutralized with ammonia;

wherein the reaction mixture the ammonium sulfonate 1s extracted with an organic solvent and is converted to the metal petroleum sulfonate.

References Cited in the file of this patent UNITED STATES PATENTS Axe et al Nov. 24, 1953 OTHER REFERENCES 

1. THE PROCESS OF MAKING AN ALKALINE EARTH METAL PETROLEUM SULFONATE WHICH COMPRISES ADDING OLEUM TO A PROPANE-FRACTIONATED, SOLVENT-EXTRACTED AND DE-WAXED LUBRICATING OIL STOCK HAVING A VISCOSITY OF ABOUT 200 TO 230 SUS AT 210*F. IN A PERIOD OF ABOUT ONE MINUTE AND WITH AGITATION; MAINTAINING THE RESULTING MIXTURE QUIESCENT FOR ABOUT ONE AND ONE HALF HOURS AT REACTION TEMPERATURE; NEUTRALIZING THE MIXTURE WITH AN ALKALINE EARTH METAL HYDROXIDE; DILUTING THE MIXTURE WITH ABOUT THREE VOLUMES OF PENTANE; AND RECOVERING THE RESULTING ALKALINE EARTH METAL PETROLEUM SULFONATE. 